Metoprolol*

• Metoprolol*

• Lopressor; Betaloc

Classification:

• Beta-adrenergic receptor blocking agent, antiarrhythmic (post MI), antihypertensive

Mechanism of Action:

• Cardioselective (β1) adrenergic blocking agent
• Reduces the incidence or recurrent myocardial infarction; reduces the size of the infarct and the incidence of fatal arrhythmias (reduced incidence of primary VF)
• Antihypertensive activity may be due to a competitive ability to antagonize catecholamine-induced tachycardia at the beta-receptor sites of the heart thus decreasing heart rate, cardiac contractility and output, inhibiting renin release by the kidneys; inhibiting the vasomotor centers
• Onset 5 minutes with a peak at 20 minutes

Indications:

• SVT
• AMI
• Unstable angina

Contraindications:

• Heart rate less than 120 bpm
• Second or third-degree heart block or significant first-degree heart block
• Evidence of STEMI on ECG
• Systolic blood pressure less than 120 mmHg
• Moderate or severe heart failure
• Known bronchospasm secondary to beta blockers

Precautions:

• Monitor EKG
• Monitor BP
• Monitor pulse oximetry
• With heart failure controlled by digoxin and diuretics, use with extreme caution
• Use cautiously in renal or hepatic failure
• Use cautiously in elderly
• Avoid use in patients with bronchospastic airway disease, may precipitate attack
• Use with caution in diabetes, may mask signs and symptoms of hypoglycemia

Adverse Effects:

• Bradycardia
• Hypotension
• Heart failure
• SOB
• Respiratory distress with laryngospasm

Dose:

• 5 mg IV q 5 – 10 min up to 3 doses.  Titrate to HR 60 – 80 if HR > 100 consider fluid bolus to ensure hypovolemia is not the cause
• Compatible with D5W and NS

• IV

• Compendium of Pharmaceuticals and Specialties (CPS)
• Pharmacology for the Prehospital Provider 2nd Edition